ABSTRACT
Assay of group-specific blood substances (GSBS) A and B was conducted in 21 series of an albumin preparation produced from donors' blood serum, in 11 series of placental and in 5 series of "Postab" albumin. GSBS content was estimated by a comparative use of poly- and monoclonal antibodies prepared in this country. More than 80% of the preparations from donors' blood serum did not contain GSBS A and B. In the preparations obtained from placental and postabortion blood the mean levels of GSBS significantly fluctuated, and with the use of poly- and monoclonal antibodies in comprised 8.3-9.1 micrograms/ml GSBS A and 16.7-42.8 micrograms/ml GSBS B, respectively. Administration to recipients of albumin preparations contaminated with GSBS may produce an immunomodulating side effect.